Method of Assembling a Fluid Separator Collection Card Assembly

ABSTRACT

A fluid sample collection card assembly in one embodiment is assembled by forming a tray assembly by supporting an absorbent layer configured to receive a fluid sample on a base portion, the base portion including a tray portion, by positioning the absorbent layer on an upper surface of a holder portion of the tray portion, the holder portion located beneath an upper surface of the tray portion, removably inserting the formed tray assembly into a tray assembly receiving cavity of a case through a mouth portion of the case, and closing, at least substantially, the mouth portion of the case with a faceplate portion of the base portion.

This application is divisional application of application Ser. No.13/921,934 filed Jun. 19, 2013, the entire contents of which isincorporated by reference herein in their entirety.

FIELD

The present disclosure relates to collection and separation ofbiological fluids. More particularly the disclosure relates to fluidsample collection devices used for collection and separation of fluidssuch as blood.

BACKGROUND

Biological samples are frequently used in laboratory and clinicalsettings to analyze various components in the samples. The biologicalsamples include blood samples, sputum samples, and urine samples. Suchsamples, for example, are used to determine the levels or concentrationsof various components such as HDL, LDL, Cholesterol, hemoglobin,detection of genes using DNA or RNA along with detection of HIVantibodies, or concentrations of drugs.

The biological sample is frequently processed in a liquid form.Accordingly, the liquid sample is collected, handled by the collectionfacility, transported to a laboratory, and stored pending processing.Activities surrounding a liquid blood sample present various problemsincluding the risk of container breakage or leakage which causes loss ofsample and the danger of infection, sample instability during shipmentand storage, transport carrier restrictions related to transport ofliquid biohazard materials, and collection of significantly more samplethan is necessary for testing so as to ensure sufficient sample quantityis available for common methods of serum or plasma preparation andsubsequent analysis. Thus, collection of several vials of fluid such asblood from a patient is not uncommon.

In response to the shortcomings of liquid sample collection, transport,and processing, various dried sample devices and methods have emerged.In dried sample devices, a biological sample is collected in the form ofa drop or two of fluid such as whole blood. The blood is collected onfilter paper and allowed to dry prior to leaving the collectionfacility. One benefit of using dried blood samples is that dried bloodsamples are not classified as a special shipping required biohazardmaterial and may be transported through the mail system or other commondelivery service just as any other package.

Additionally, even when a blood or other fluid sample is removed fromthe body, the concentration of various components within the sample canchange over time due to various ongoing reactions. For example,biochemical and cellular changes, such as red blood cells metabolizingplasma glucose for continued cellular respiration, continue in liquidsamples. Additionally, when using dried whole blood collection methods,such as collection on Whatman 903 filter paper, as the blood dries, thered cells hemolyze which then becomes mixed with red blood cell membranecholesterol. The red blood cell membrane cholesterol, which is notnormally in the serum portion of the blood, then becomes mixed in withserum cholesterol. Such a mixing may yield a clinically significantincrease in a patient cholesterol result. Dried fluid samples have theadvantage of reducing various reactions, thereby preserving certaincomponents for later analysis.

The transportation and handling of dried fluid samples is thus asignificant improvement over transportation and handling of liquidsamples. Merely drying a fluid sample does not always ensure theusefulness of the sample. By way of example, in order to performanalysis of certain dissolved blood components a whole blood samplecannot be used. For example, hemoglobin can interfere with serumanalytes at the light absorbance in the instrumental step of clinicalanalyte testing. Accordingly, the red blood cells must first beseparated from the blood plasma or serum prior to drying. The mostconventional manner of separating serum or plasma from blood cells is bycentrifugation. Centrifugation, of course, requires more than a fewdrops of blood. Additionally, expensive and space consuming equipmentmust be maintained at the collection site to perform centrifugation.

Various approaches have been developed to provide for separation ofblood samples prior to drying of the samples. For example, U.S. Pat. No.5,064,541, issued to Jeng et al. on Nov. 12, 1991, describes a devicewhich separates plasma from red blood cells that uses an agglutinationagent in a filter to clump red blood cells together. The incorporationof an additional biochemical filter in the device adds to the complexityand cost of the device. Additionally, the amount of blood collected mayoverwhelm the ability of the red blood cell agglutinating agent to workon all of the red blood cells applied in the whole blood sample.

U.S. Pat. No. 4,816,224, issued to Vogel, et al. on Mar. 28, 1989,describes a series of wicking papers and a relative large sample holderwith different embodiments that contain many different components. Thedevice is complex and requires significant foot print space whenshipping or undergoing sample extraction at a remote laboratory.

U.S. Pat. No. 6,258,045, issued to Ray et al. on Jul. 10, 2001,describes a device which requires tubing for capillary collection ofwhole blood along with filtration and multiple layers of reactive ornon-reactive materials for plasma separation and testing. Capillarycollection tubes require a certain level of operator experience andinflict additional pain on the patient when compared to a simple lancetstick. Additionally, the glass tube can be broken or become detached.

Traditional devices for obtaining dried fluid samples furtherincorporate indirect methods for ensuring that the proper amount offluid has been collected to allow the desired separation. Some devicesincorporate an indicator which changes color or a portion of the stripwhich provides a chemical reaction. Such devices do not provide anindication of whether or not too large a sample of fluid has beencollected.

Therefore, a collecting device that is self-contained and can be used toprovide stable dried biological components to a laboratory would bebeneficial. Further benefits would be realized if the device is simpleto manufacture and provides accurate results. Further benefits would beprovided by a device which enables both the sample collector andlaboratory personal to visually directly observe the amount of fluids,such as serum or plasma or red blood cells, which have been collected. Adevice that can be used to separate fluids such as blood into separatecomponents and which is easy to mail without additional charges wouldalso be beneficial.

SUMMARY

The present disclosure is directed to assembling a device for separatingand drying a fluid sample. In one embodiment, a method of assembling afluid sample collection card assembly includes forming a tray assemblyby supporting an absorbent layer configured to receive a fluid sample ona base portion, the base portion including a tray portion, bypositioning the absorbent layer on an upper surface of a holder portionof the tray portion, the holder portion located beneath an upper surfaceof the tray portion, removably inserting the formed tray assembly into atray assembly receiving cavity of a case through a mouth portion of thecase, and closing, at least substantially, the mouth portion of the casewith a faceplate portion of the base portion.

In one or more embodiments, forming the tray assembly further includessecuring the absorbent layer configured to receive a fluid sample to theupper surface of the holder portion with an insert.

In one or more embodiments securing the absorbent layer configured toreceive a fluid sample to the upper surface of the holder portion withthe insert includes frictionally engaging the holder with the insert.

In one or more embodiments, assembling a device for separating anddrying a fluid sample includes providing a bridge in the insert, thebridge stiffening the insert to provide increased frictional engagementbetween the holder and the insert when frictionally engaging the holderwith the insert.

In one or more embodiments, providing the bridge includes defining, atleast in part, a sample window with the bridge.

In one or more embodiments, defining, at least in part, the samplewindow with the bridge includes defining the sample window at a locationwhereat when the absorbent layer is secured to the upper surface of theholder portion, the sample window is located directly above a samplereceiving portion of the absorbent layer which is positioned on anon-absorbent ledge of the base portion.

In one or more embodiments, assembling a device for separating anddrying a fluid sample includes defining, at least in part, a portion ofa viewing window.

In one or more embodiments, supporting the absorbent layer configured toreceive a fluid sample on the base portion further includes positioningthe absorbent layer configured to receive a fluid sample on a lip of theholder portion, the lip defining an opening in the base portion.

In one or more embodiments, removably inserting the formed tray assemblyinto a tray assembly receiving cavity of a case includes removablyinserting the formed tray assembly into a tray assembly receiving cavityof a case including at least one ventilation hole extending from thetray assembly receiving cavity to an outer surface of the case.

In one or more embodiments, removably inserting the formed tray assemblyinto the tray assembly receiving cavity includes guiding opposing sidesof the tray portion at least one pair of rails extending along the trayassembly receiving cavity.

In one or more embodiments, closing, at least substantially, the mouthportion of the case with the faceplate portion of the base portionincludes abutting a portion of the case with the faceplate portion whenthe tray portion is received within the tray assembly receiving cavity.

These and other advantages and features of the present disclosure may bediscerned from reviewing the accompanying drawings and the detaileddescription of the preferred embodiment of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may take form in various system and methodcomponents and arrangement of system and method components. The drawingsare only for purposes of illustrating exemplary embodiments and are notto be construed as limiting the disclosure.

FIG. 1 depicts a top perspective view of a separator card assemblyincluding a tray assembly with a sample receiving portion of anabsorbent layer accessible through an sample window and a sampleindicating portion of the absorbent layer viewable through a viewingwindow in accordance with principles of the disclosure;

FIG. 2 depicts a perspective view of the case of FIG. 1;

FIG. 3 depicts a perspective view of the tray assembly of FIG. 1 showingreference marks on an upper surface of a tray portion and a samplereceiving portion of the absorbent layer accessible through a samplewindow portion of an insert and a sample portion of the absorbent layerviewable through a sample viewing portion of the insert;

FIG. 4 depicts an exploded perspective view of the tray assembly of FIG.3;

FIG. 5 depicts a top, rear perspective view of the tray portion of thetray assembly of FIG. 3;

FIG. 6 depicts a perspective view of a resealable packet that may beused to transfer the separator card assembly of FIG. 1 through a carrierservice to a laboratory or other facility; and

FIG. 7 depicts a perspective view of a removal tool that may be used toseparate at least a portion of the absorbent strip of the separator cardassembly of FIG. 1.

DESCRIPTION

Referring to FIG. 1, a fluid separator card assembly 100 is shown whichin this embodiment is configured to separate serum and plasma in a bloodsample. The fluid separator card assembly 100 includes a case 102 and atray assembly 104. In one embodiment, the case 102 has a depth (from theupper surface to the lower surface as depicted in FIG. 1) of about ¼inch or less, preferably about ⅜ inch. The case 102, also shown in FIG.2, includes a ventilation hole 106 and a ventilation hole 108. Two pairof rails 110 and 112 are located on opposite sides of the case 102. Therail pairs 110 and 112 extend from a mouth 114 at a forward end portion116 of the case 102 to a rear end portion 118 of the case which in thisembodiment is sealed. The rail pairs 110 and 112 define a pair ofopposed grooves 120 and 122, respectively. The mouth 114 provides accessto a tray assembly receiving cavity 124 in which the rail pairs 110 and112 and opposed grooves 120 and 122 are located.

The opposed grooves 120 and 122 are sized and positioned to receive thetray assembly 104 shown in further detail in FIGS. 3 and 4. The trayassembly 104 includes a base portion 130, an absorbent layer 132, and aninsert 134. The base portion 130 includes a tray portion 140 and afaceplate 142. A holder portion 144 in the tray portion 140 includes anopening 146 which is surrounded by a lip 148. The lip 148 includes anon-absorbent ledge 150.

In the embodiment of FIGS. 1-5, a series of reference marks 152, 154,and 156, which extend outwardly from the sides of the holder portion,along with an identification block 158 are provided. Alternatively, thereference marks 152, 154, and 156 and/or the identification block 158are provided on the insert 134. In some embodiments, either thereference marks 152, 154, and 156 and/or the identification block 158 isomitted. In other embodiments, more or fewer reference marks 152, 154,and 156 are provided. Instructions for using the separator card assembly100 may be printed in the identification block 158 and space forinsertion of patient identification data may also be provided therein.

The insert 134 includes an outer frame portion 162 and a bridge 164which extends between opposite sides of the frame portion 162. The frameportion 162 and the bridge 164 define a sample window 166 and a viewingwindow 168. The insert 134 in some embodiments is formed from a polymeror other nonabsorbent material.

The tray portion 140 in one embodiment is fabricated from a polymer orother nonabsorbent material. In some embodiments, the ledge 150 includesa well or depression (not shown) into which excess fluid sample poolsuntil absorbed by the absorbent layer 132. In other embodiments, theledge 150 is omitted and the opening 146 extends to a location adjacentto the faceplate 142.

In some embodiments, including embodiments wherein the ledge 150 isconstructed of an absorbent material, a non-absorbent material is usedto line the ledge 150. The non-absorbent material in some embodiments isMylar, which is used for its imperviousness to liquid penetration. Othermaterials which may be used to form an acceptable liquid barrier includethin sheets of Polyethylene, porous UHMWPE film, FEP film, polyestertreated sheeting and polypropylene.

Another material which provides an acceptable liquid barrier is porousePTF film, commercially available from DeWal Industries, Inc. ofSaunderstown, R.I. as product number D/W 233MS. The ePTF material is afluoropolymer material which contains a fluorocarbon material at itssurface. The fluorine molecule is the most electronegative element,thereby providing a desired hydrophobic quality. Specifically, it isbelieved that the fluorocarbon additive to the base plastic polymer inthis material and other fluoropolymers enhances the separation of plasmafrom the red blood cells in the touching absorbent layer 132.

The tray assembly 104 is assembled by inserting the absorbent layer 132into the holder portion 144 of the base portion 130 on top of the lip148 (see FIG. 4). The absorbent layer 132 is sized to contact the lip148 on all sides of the opening 146. Preferably, the absorbent layer 132does not extend up the wall extending from the lip 148 to the uppersurface of the tray portion 140. The absorbent layer 132 in thisembodiment is made from Whatman LF-1 material, commercially availablefrom Whatman Inc. of Florham Park, N.J. Other suitable material may beused, such as, but not limited to, porous materials that allow liquidand suspended solids to differentially flow and separate based on themolecular size of the molecules.

Additionally, the characteristics of the absorbent layer 132 may bemodified by incorporating designs that utilize other physical forcesthat affect the flow of substances through the absorbent layer 132. Suchphysical forces include hydrophobic or hydrophilic interactions as wellas ionic interactions. Additionally, temporary hydrogen bondinginteractions and gravitational effects may be used to augment or retardflow to provide the desired separation or alteration of a separation ofthe flowing liquids and suspended cells or other solid materials.

The insert 134 is then positioned within the holder portion 144 on topof the absorbent layer 132. The insert 134 is sized to be at leastslightly longer and wider than the holder portion 140. Accordingly, asthe insert 134 is positioned within the holder portion 140, the insert134 frictionally engages the walls of the holder portion 144 trappingthe absorbent layer against the lip 148. As shown most clearly in FIG.4, the ledge 150 is substantially coextensive with the sample window 166when the ledge 150 and the sample window 166 are projected onto a planedefined by the tray portion 140.

Amongst other functions, the bridge 164 provides additional stiffness,thereby providing for increased friction. Accordingly, in someembodiments, additional bridges are provided to provide additionalstiffness. In some embodiments, the bridges are used in place of thereference marks 152, 154, and 156.

In some embodiments, the bridge 164 is omitted. For example, the bridge164 may be omitted in embodiments where the material used to constructthe insert 134 is sufficiently stiff to provide the desired friction alhold or in embodiments where the insert 134 is sonically welded orotherwise attached to the holder portion 144.

Once the absorbent layer 132 is secured on the tray portion 140, thetray assembly 104 is positioned in the case 102 by aligning the trayportion 140 with the grooves 120/122. The tray assembly 104 is thenpushed through the mouth 114 and into the tray assembly receiving cavity124 until the faceplate 142 substantially closes the mouth 114.

In some embodiments, a small stand-off is established between thefaceplate 142 and the case 102 to provide for ventilation of the trayassembly receiving cavity 124. The standoff may be accomplished byproviding a protuberance on either the case 102 or the faceplate 142. Inthe embodiment of FIG. 1, the faceplate 142 contacts the case 102. Insome embodiments, a latch or other configuration is provided toremovably secure the tray assembly 104 within the case 102. By way ofexample, the tray portion 140 in some embodiments is provided with aprotuberance (not shown) which engages a hollowed portion of one of therails 110/112.

The assembled separator card assembly 100 may be further packaged forstorage until a fluid sample is needed. A fluid sample may be obtainedin a clinical or laboratory setting. Alternatively, the separator card100 may be used by lay persons at virtually any location. When a sampleis to be collected, a user at least partially removes the tray assembly104 from the case 102. Removal of the tray assembly 104 is facilitatedin the embodiment of FIG. 1 in that a portion of the faceplate 142extends above the upper surface of the case 102 as shown in FIG. 1. Inother embodiments, a tab is provided. Accordingly, a user pushes againstthe faceplate 142 to force the tray assembly 104 away from the case 102.

The tray assembly 104 is moved outwardly at least until the samplewindow 166 is exposed. A sample is obtained by producing the fluid, suchas by pricking a finger to obtain blood. Four to five drops of blood orother fluid is then dripped onto the absorbent layer 132 through thesample window 166 such that the fluid sample contacts the absorbentlayer 132. In embodiments which do not include a bridge 164 defining asample receiving portion of the absorbent layer 132, the samplereceiving portion of the absorbent layer 132 is indicated in anothermanner such as by marking on the absorbent layer 132 or by a mark on theinsert 134 or upper surface of the tray portion 140.

When the fluid sample contacts the absorbent layer 132, the sample iswicked by the absorbent layer 132, and preferentially aided in movementand separation by the chemical or physical nature of the ledge 150, intothe portion of the absorbent layer 132 viewable through the viewingwindow 168. As additional fluid is placed into the portion of theabsorbent layer 132 accessible through the sample window 166, the wickedfluid will become visible through the viewing window 168.

In embodiments simply requiring 4 to 5 drops of blood, the referencemarks 152, 154, and 156 may be omitted, and collection of fluidterminated once the requisite number of drops has been provided. Inother embodiments, the reference marks 152, 154, and 156 are used toindicate when a sufficient amount of fluid has been provided.

Specifically, once the fluid reaches the reference line 152 as fluid iscontinuing to be provided to the sample portion of the absorbent layer132, sufficient fluid has been absorbed to perform a single test on theseparated portion of the fluid. Thus, in the case of blood, plasma willbe wicked along the absorbent layer 132. When the plasma reaches thereference line 152, provision of blood is terminated if a single test isto be performed. The plasma will continue to wick beyond the referenceline, thereby providing sufficient plasma for conducting a single test.

The reference lines 154 and 156 may be provided to indicate whensufficient blood or other fluid has been absorbed to separate a quantityof plasma or other fluid component necessary for performance of twotests and three tests, respectively.

The amount of fluid that is necessary to obtain the desired amount offluid component will vary based not only on the materials used, but alsobased upon the geometry of the channel formed. By way of example, usingmaterials identified above absorbent layers may be formed with a widthof from about 0.6 centimeters to about 4 centimeters when separatingplasma from a blood sample. Optimum separation of plasma, however, isobtained with a width of about 1 centimeter. By optimizing theseparation of the plasma, less blood is needed to obtain a particularamount of plasma.

The length of the absorbent layer 132 is also a consideration inensuring sufficient separation of a sample fluid. By way of example, asthe volume of sample fluid deposited in the absorbent layer 132increases, the red blood cells, in the case of blood, will travelfurther along the absorbent layer 132. Thus, to ensure that a sufficientseparation of a sample fluid occurs in the event too much sample isprovided, the length of the absorbent layer 132 may be increased.

Once the desired sample has been collected, the absorbent layer 132 isleft to dry. If desired, the tray assembly 104 may be reinserted intothe case 102 in the manner described above while the absorbent layer 132is still damp. The ventilation holes 106/108 which extend from the trayassembly receiving cavity 124 to the atmosphere outside of the case 102assist with drying. Preferably the ventilation holes 106/108 arepositioned such that if an object is inserted through the ventilationholes 106/108, the object will contact the tray portion 140 and not theabsorbent layer 132. For example, as depicted in FIGS. 1 and 2, theventilation holes 106/108 are located at the outer edges of the case. Insome embodiments, the ventilation holes 106/108 are sized such thatliquids will not readily be passed through the ventilation holes 106/108to further protect the obtained sample from contamination.

The separator card assembly 100 may then be shipped via any desired modeof transportation to a processing facility. The dried fluid samplecontained in the absorbent layer 132 may be stored for a relatively longtime without undue degradation of the sample. Nonetheless, the shelflife of the sample may be extended by placement of the separator cardassembly 100 in a storage container such as the package 180 shown inFIG. 6.

The package 180 is a gas impermeable package such as a plastic or foilpackage. The package 180 includes a resealable opening 182. Theresealable opening 182 may include a tamper proof mechanism to providean indication that the package 180 has been opened after a sample hasbeen sealed therein. The package 180 is sized to accept the separatorcard assembly 100 therein, and may be further dimensioned to allow forinsertion into a flat envelope of standard size for automated processingby a postal facility. Alternatively, the package 180 may include apreprinted address 184 and prepaid postage 186 as in the embodiment ofFIG. 6.

In one embodiment, an oxygen scrubber (not shown) is provided with thepackage 180. An oxygen scrubber typically includes thin shavingsincluding pieces of metal and a carrier desiccant that loosely holdssome amount of water. When the package 180 is sealed with an oxygenscrubber therein, oxygen present within the package 180 reacts with themetal in the presence of water to form rust, thereby binding the oxygen.Elimination of oxygen from the atmosphere of the package 180 providesincreased stability for various components within the dried fluidsample. For example, lipid analytes such as HDL, cholesterol, andtriglycerides may be further stabilized by removal of oxygen from theatmosphere in which the sample is stored.

If desired, the separator card assembly 100 may be placed within thepackage 180 and the package 180 sealed before a fluid sample within theabsorbent layer 132 has been dried. Sealing the package 180 with a wetfluid sample held in the separator card assembly 100 inhibits drying ofthe sample.

Removal of at least a portion of the absorbent layer 132 from the trayassembly 104 for further processing is facilitated by the opening 146.One device that may be used to remove at least a portion of theabsorbent layer 132 is the removal tool 190 shown in FIG. 7. The removaltool 190 includes a lever arm 192, a guide stop 194, an upper mandrel196 and a lower mandrel 198. The lower mandrel 198 includes a shapedcutting edge 200 which is sized to fit inside both the viewing window168 and the opening 146. The upper mandrel 196 includes a protuberance(not shown) that is slightly smaller than the viewing window 168 and theopening 146 and positioned to fit within the shaped cutting edge 200.

Accordingly, removal of the portion of the absorbent layer 132 includingthe separated sample is accomplished by removing the tray assembly 104from the case 102 as described above and placing the tray assembly 104on the removal tool 190. Correct placement of the tray assembly 104 onthe removal tool 190 may be guided by the guide stop 194. Alternatively,the viewing window 168 and opening 146 are simply positioned over theshaped cutting edge 200. Thereafter, movement of the lever arm 192 inthe direction of the arrow 202 forces the protuberance (not shown) onthe upper mandrel 196 against the absorbent layer 132 at a locationaligned with the viewing window 168 and opening 146. The portion of theabsorbent layer 132 viewable through the viewing window 168 is thusforced against the shaped cutting edge 200 which separates the portionof the absorbent layer 132 including the separated sample from the trayassembly 104.

Various other modifications of the separator card assembly 100 may beincorporated to optimize the separator card for particular tests. In oneembodiment, polyhexamethylene biguanide hydrochloride (PHMB) isincorporated into the absorbent layer 104. PHMB is an additive used inbandages for inhibiting the growth of microbial organisms such asbacteria and fungi.

In a further embodiment, prior to blood or other biological fluidapplication, a polypeptide fraction of highly purified dermal collagenof porcine origin (Prionex from Pentapharm) is applied and dried to theseparator card absorbent layer 104. A separator card 100 treated withPrionex applied to the absorbent layer 104 at a 0.1 percentconcentration can yield close to double the separation area of serum orplasma for a given volume of blood applied to the absorbent layer 104.Other substances such as various proteins, detergents, salts orsolvents, or other chemicals may also be used to enhance separation of asample fluid.

Another additive that is useful when obtaining fluid samples in the formof blood is sucrose. In particular, cholesterol containing molecules andcholesterol itself are hydrophobic molecules which in pure form do notmix with an aqueous solution. The complex arrangement of proteins, saltsand carbohydrate and complex carbohydrate in blood, however, holds thesehydrophobic molecules in suspension. Disruption of these serumcomponents during drying could result in clumping or aggregation of thehydrophobic molecules rendering successful hydration of the hydrophobicmolecules problematic.

Application of sucrose in 1 to 10% wt./vol. concentration followed bydrying to the absorbent layer 104, however, provides a more reproducibledrying and rehydration of cholesterol containing molecules such as HDL,LDL and the cholesterol molecule itself. It is believed that thecarbohydrate sucrose molecules are surrounded by water molecules when afluid sample is added. Thus, the sucrose layers surround the hydrophobiccholesterol or triglyceride molecules during the drying and inhibitaggregation via hydrophobic binding of the sucrose shielded hydrophobicmolecules.

While the present disclosure has been illustrated by the description ofexemplary processes and system components, and while the variousprocesses and components have been described in considerable detail,applicant does not intend to restrict or in any limit the scope of theappended claims to such detail. Additional advantages and modificationswill also readily appear to those skilled in the art. The disclosure inits broadest aspects is therefore not limited to the specific details,implementations, or illustrative examples shown and described.Accordingly, departures may be made from such details without departingfrom the spirit or scope of applicant's general inventive concept.

1. A method of assembling a fluid sample collection card assemblycomprising: forming a tray assembly by supporting an absorbent layerconfigured to receive a fluid sample on a base portion, the base portionincluding a tray portion, by positioning the absorbent layer on an uppersurface of a holder portion of the tray portion, the holder portionlocated beneath an upper surface of the tray portion; removablyinserting the formed tray assembly into a tray assembly receiving cavityof a case through a mouth portion of the case; and closing, at leastsubstantially, the mouth portion of the case with a faceplate portion ofthe base portion.
 2. The method of claim 1, wherein forming the trayassembly further comprises: securing the absorbent layer configured toreceive a fluid sample to the upper surface of the holder portion withan insert.
 3. The method of claim 2, wherein securing the absorbentlayer configured to receive a fluid sample to the upper surface of theholder portion with the insert comprises; frictionally engaging theholder with the insert.
 4. The method of claim 3, further comprising:providing a bridge in the insert, the bridge stiffening the insert toprovide increased frictional engagement between the holder and theinsert when frictionally engaging the holder with the insert.
 5. Themethod of claim 4, wherein providing the bridge comprises: defining, atleast in part, a sample window with the bridge.
 6. The method of claim5, wherein defining, at least in part, the sample window with the bridgecomprises: defining the sample window at a location whereat when theabsorbent layer is secured to the upper surface of the holder portion,the sample window is located directly above a sample receiving portionof the absorbent layer which is positioned on a non-absorbent ledge ofthe base portion.
 7. The method of claim 6, wherein defining, at leastin part, the sample window with the bridge further comprises: defining,at least in part, a portion of a viewing window.
 8. The method of claim7, wherein supporting the absorbent layer configured to receive a fluidsample on the base portion further comprises: positioning the absorbentlayer configured to receive a fluid sample on a lip of the holderportion, the lip defining an opening in the base portion.
 9. The methodof claim 1, wherein removably inserting the formed tray assembly into atray assembly receiving cavity of a case comprises: removably insertingthe formed tray assembly into a tray assembly receiving cavity of a caseincluding at least one ventilation hole extending from the tray assemblyreceiving cavity to an outer surface of the case.
 10. The method ofclaim 1, wherein removably inserting the formed tray assembly into thetray assembly receiving cavity comprises: guiding opposing sides of thetray portion at least one pair of rails extending along the trayassembly receiving cavity.
 11. The method of claim 1, wherein closing,at least substantially, the mouth portion of the case with the faceplateportion of the base portion comprises: abutting a portion of the casewith the faceplate portion when the tray portion is received within thetray assembly receiving cavity.